1. Field of the Invention
This invention refers to a angular movement restriction bushing for ball joint, for application in connections which require angular and rotational movement of two pieces, wherein however the angular movement needs to be restricted in a certain direction, in order to obtain the desired technical effect and, more particularly, this invention deals with a bushing for ball joint to be applied in automotive vehicles.
2. Description of Related Art
The usual technique for the construction of the ball joints is based on a construction composed of a box or receptacle where is housed a single bearing or split bearing that, by its turn, houses a ball that is disposed as an integral part of the end of a pin, the so-called ball pin. This assembly, duly mounted, has a fixing system at the external part of the box or receptacle, the same occurring at the end opposite to the ball, of the so-called ball pin, in such a way that, once the box is fixed in a mobile piece and the body of the ball pin in another one, provides to both pieces, angular and rotational movements. These are the usual constructions of ball joints, generally employed in the steering and suspension systems of a vehicle, but, depending on the place where they are to be applied, the same, individually, have specificities, which aim to attend the operating requirements demanded of the pieces that must be connected and pivoted.
In the scope of this invention, the ball joint with the angular movement restriction bushing needs to allow the free rotational movement of the ball pin but, at the same time, to restrict the angular movement of this same ball pin in certain direction, as it is applied, preferably, in steering or connecting rods in which it is undesirable the movement of rotation relative to the longitudinal axles contained in the same. The rotational movement of the rod relative to its longitudinal axle forces the ball pin to displace angularly toward one of the sides of the ball joint box, causing the inadequate operation of the ball joint itself and further of the rod itself, that has been designed to operate aligned to the other components of the system. To overcome these deficiencies, the state of the art preceding this invention has employed until now as an alternative, to position the oblong opening of the ball joint box, that is common in this type of construction, through which is projected the body of the ball pin, in such a way that the narrowest side of the opening, that is, the side that allows shorter angularity in the movement of the ball pin, is coincident with the plan where it is desired to restrict the movement of the ball pin, and this prevents the bar from rotating around its longitudinal axle. This technique, as it is obvious to infer, does not solve the problem, as this prevents the rod from rotating around its longitudinal axle, and this only occurs because the body of the ball pin of the ball joint has displaced to its maximum limit of angularity to that side and abuts the oblong opening of the ball joint box. Thus, while this partially solves the problem of rotation of the rod, another problem is caused, namely the inadequate operation of the ball joint, with its ball pin working leaned against the opening of the box, therefore outside of its geometrical axle, as it has been designed.
This inadequate operation of the ball joint will cause deficiency of movement, premature wearing out, noises and other undesirable inconveniences. Aiming to solve these inconveniences of inadequate operation of the ball joint, the state of art, also precedent to this invention, developed some systems that consisted in replacing the protection cover of the ball joint by a kind of rubber bushing which, when the assembling of the ball joint on the rod is carried out, the same is compressed causing a spring like effect, which in cooperation with the narrowest part of the oblong opening of the ball joint box, has as purpose to avoid the rotation, preventing the same from displacing itself around its longitudinal axle, at the same time that it holds, when the strain is not great, the ball pin of the ball joint in the geometrical axle in which it was designed. However, until now, also this technique has not presented the effects that are desirable, as, when one substitutes the protection cover by the rubber bushing, this latter must be constructed in such a way as to provide to the ball joint the same sealing effect provided by the protection cover. In order to attain this objective, the prior art technique required additional processes of machining in the ball joint and a special construction system for the rubber bushing in order to make possible that the same performs the two functions, namely, that of sealing the opening of the ball joint and that of providing the spring like effect so that the ball pin of the ball joint be maintained in its designed geometrical axle. This system, besides making the end product more expensive, has a low index of applicability, as its use is limited to rods with few movements and, consequently, they do not produce a great strain upon the ball pin. Further, in function of the constant strain upon the rubber bushing, this latter tends to deteriorate prematurely the working lifetime of the ball joint, what will affect the sealing system and, as a consequence, with this negative action, the ball joint will be contaminated by impurities such as dust, sand and water, causing its premature wearing out.
Apart from the above-described technique, there are other systems developed with the same objective of restricting the angular movement of the ball joint in a certain direction but, as they are systems utilized in rods with a wide range of displacements, namely, of generic applicability, irrespective of the movement of the bar, they are complex and high cost systems, as they require the construction of an extension in the ball section of the ball pin and, in complement, the construction of a special cover for the ball joint box, through which is projected the body of the ball pin. These system function to house the extension of the ball section of the ball pin, to, in cooperation with the oblong opening of the box, restrict the angular movement of the ball pin in a certain direction. These systems are efficient, but, rather expensive, as it can be deducted from the above description and, when the ball joint is intended for rods with few movement, the high cost of these systems economically render unfeasible its use for this specific and limited utilization.
Thus, in the scope of this invention, a bushing that restricts the angular movement for ball joint thus suppressing the deficiencies existent in the state of the art, with low cost, high durability and, mainly, with an efficient sealing system that, concomitantly substitutes the protecting cover of the ball joint, restricts its angular movement in a certain direction, produces the spring like effect maintaining the ball pin always in its designed geometrical axle, and has high durability, as it does not submit the material of the bushing, constructed of elastomer, to excessive strains.